Unfortunately, it is very hard to protect your intellectual property from being stolen on the Internet. There are numerous websites that allow unauthorized users to copy and distribute your work, and they can easily upload it to other sites without your permission. You can try to notify the site's administrators, but this can be a lengthy process.
1. According to the NFTStreet, you should never upload source files or images that are in the lowest quality. Doing so can help prevent unauthorized users from accessing your content. Even if your work is tied to a token, buyers will most likely not buy it from the attacker.
2. Try to copyright your work and share it on social media.
3. You can also protect yourself from the theft of your NFT tokens by signing up for an account with a different e-Wallet such as OpenSea, Rarible, or Nifty Gateway. To do so, enter a phrase that's 12 words long.
4. When looking for a site in the search engine, always pay attention to the address bar and not to the page itself. Fake mirror sites that look like they're from OpenSea or Rarible might look similar, but they have additional symbols and letters in the address bar.
5. Never use the same passphrase on multiple websites. Also, do not report it even if it's asked for by a support agent from one of the platforms you're on.
6. Follow your fans on social media to keep track of the activities of those who steal your work. They can then report the illegal activity to authorities.
7. You can also protect yourself from the theft of your art by preserving the original source files on an offline media. Doing so can help prevent unauthorized users from accessing your content.
8. To prevent unauthorized users from accessing your content, close all of your old accounts. Doing so will prevent them from stealing it and passing it off as your own work.
9. If you're on Twitter, you can also block the accounts that are associated with the @tokenized tweets bot account. To do so, go to the "NFT Blocklist" section and search for the account.
10. If you still found your work on one of the sites, write complaints to support. It's better than doing nothing.